Download 11/17: Food Chains

Food Chains
Lecture 7
Honors and General Marine Biology
Ecosystems
Ecosystems – The biotic community and its abiotic
environment functioning as a system.
What are the parts
of the ecosystem
pictured at left?
What are the biotic
and abiotic factors
here?
How do they affect
the food chain?
What about your
“ecosystem”?
What did you have to eat today?
Where did
the energy
come from
to make this
food?
Autotrophs
Autotrophs – Those organisms that can
harness
the suns energy and make their own food.
Auto (Automatic) =
Self
Troph =
Feeding
Examples of Marine Autotrophs:
Because they can make their own food, and food for
others, they are called Producers. All autotrophs are
Photosynthetic (or Chemosynthetic).
Heterotrophs
Heterotrophs – Those organisms that can not make
their own food. Must eat other things, and so are
also called Consumers.
Examples of Consumers
Types of Heterotrophs
Can be classified into three types:
1.
2.
3.
Herbivores –
Eat Plant
matter.
Carnivores –
Eat Animal
Matter
Omnivore –
Eat Both.
Decomposers
Decomposers – Are the organisms that eat all dead
material, including wastes of others.
The
“Garbage men” of the environment.
i.e.
Bacteria.
How do they all interact?
Look at the hand-out. This is a simple Food Chain.
Food Chains
Food Chains – Diagrams
that map the linear flow
of energy (and Biomass)
though an ecosystem.
Based on the nutritional
requirements of the
organisms.
Is this how nature works?
NO!
Food Webs
Food Webs –
Show the
complex
interrelationships
among
organisms.
However,
What is
missing?
Energy
Marine Webs can extend onto the land.
Food Pyramids
Trophic Levels – refers to
Feeding Levels.
Each Level gets smaller in
Energy and Biomass.
Why?
10% Rule – Only 10% of
the energy/biomass at
one level is available for
energy/biomass at the
next level.
Lets look at the hand-out again.
What are the trophoc levels we see?
1st trophic level = Producers
•Microscopic (in marine are mostly)
•Photosynthetic, produce own food.
•Ex. Phytoplankton, algae
2nd trophic level = Primary consumers
•Very Small (microscopic?) herbivores.
•Feed on producers such as phyto and alage.
•Ex. Copepods (like little shrimp) and krill.
3rd trophic level = secondary consumers
•Small Carnivores plus……
•Feed on primary consumers.
•Examples are mussels, small fish (anchovies), clams and
baleen whales.
Hand-Out Analysis Con’t
4th trophic level = tertiary consumers
•Even larger carnivores.
•Examples larger fish (Tuna), seals and
birds.
5th trophic level = quaternary consumers
•Largest fish such as sharks and
toothed whales.
The last “level”
Decomposers
•Bacteria and fungi
•Eat dead remains or wastes on
seafloor.
NOTE: Nutrients are recycled….ENERGY IS NOT!!
Food Chains/Webs Activity
You have three tasks.
1)Make a food web of local marine life. You must include ten
species that are interspaced between the different trophic
levels. You may use phytoplankton and zooplankton as generic
first two levels.
2)Using your food web, trace a pathway to make a food chain.
Draw the food chain of your food web.
3)Using the food chain, start with 1,000,000 grams of
phytoplankton biomass. Show the resulting biomass of each
trophic level of your food chain.
Whales and food Chains?
Using the food pyramid, why can whales get so big?